Cooling system for vapor lamps



April 1942- I c. R. DUNITHAM ETAL 2,279,941

COOLING SYSTEM, FOR VAPOR LAMPS Filed Jan. 27, 1941 lnven'tor's: Carlton Eo'sstgn Dunham, 1, Vic'L'ov James Francis, 9 V Their A'tfQrneg.

Patented Apr. 14,- 1942 srss EATENT.

.coouso srsran roa varon s i Carlton R. Dunham, London, and Victor J. Fran cis, North Wembley, England, assignors to General Electric Company, a corporation of New York Application sanitar 21, 1941, Serial No. 376,229

In Great Britain January. 12, 1940 g 6 Claims. (01. 176-124) This invention relates to combinations of a high pressure metal (mercury) vapor lamp, ,referred to hereafter as a HPMV lamp, with means for cooling it of the type wherein the operation of the cooling means is controlled by the current period may not be prolonged, (c) that it should operate when the lamp has just been extin guished owing to a drop in the supply voltage, in order that the lamp may cool down rapidly and start again as soon as possible, (it) that no part of the controlling means should ever be exposed to an excessive voltage. is operated electrically-from the supply that feeds the lamp, it is impossible to secure (0) completely for the blowercannot operate while the supply is completely off or below some limiting voltage. It is sufficient for (c) if the blower operates so long as the lamp is on but the supply on.

It is an object of the invention to provide an :2;

arrangement in which these conditions are fulfilled, preferably automatically, but possibly with some manual operation. Further objects and advantages will appear from a consideration of the following detailed description and the accompanying drawing which shows diagrammatically a circuit embodying the invention in its preferred form.

Referring to the single figure of thedrawing,

the combination shown is of the type specified and comprises lamp I, preferably for the HPMV type and energized by current from supply lines 2--2 through stabilizing impedance 3, and three relays A, B and C. .13 operates and sets the blower into operation if, but only if, the voltage across the lamp attains a value greater than the normal of the lamp. C operates if but only if, current is passing through the lamp and, when it operates, applies to A/the voltage across the lamp.

When the lamp is first switched on and the dis- If the blower charge starts, C operates; but neither nor'B operates because the voltage across them is too low; consequently the blower is not operated. When the heating-up process has progressed to a desirable stage, A operates, whereupon the blower starts and continues as long as the lamp is in operation. If the lamp is extinguished by even a momentary drop in supply voltage, C drops out and prevents the application to A of the excessive voltage to which it would otherwise be exposed if thesupply voltage remained at or returned to a value not much less than its normal value. But if the supply voltage remains at, or

when it returns to, such a voltage, B operates and the blower is operated. When the lamp starts again, B ceases to be operated because the voltage across the lamp falls; but now C is operated and prepares for the operation of A when a suflicient part of the heating-up process is completed.

Since B is called into action only when the lamp is extinguished, it may be replaced by'a manually operated switch, if the lamp is attended; for the operator will always be aware of the extinction of the lamp. Such a departure from the, preferred form of the invention is permissible; on the other hand A and C must operate according to the statement of the said preferred form.

What we. claim as new and desireto secure by Letters Patent ofthe United States is:

1. In combination with a vapor electrical dis charge device and a sourceof power therefor, cooling means for said device, first relay means responsive to the-voltage of said device for ener sizing said cooling means when approximate normal operating conditions obtain, means for deenergizing said relay means when the voltage across said device becomes substantially higher than normal operating voltage, and second relay means responsive to voltages greater than said normal operating voltage but less than the voltage'of said source for energizing said cooling means when the voltage across said device hecomes substantially higher than. said normal op erating voltage.

2. In combination with a vapor electrical discharge device and a source of power therefor, cooling means for said device, first relay means responsive to the voltage of'said device for energizing said cooling means when approximate normal operating conditions obtain, means for deenergizing said relay means when said device becomes temporarily deenergized after normal operation has once obtained, and second relay means responsive to the voltages across said lamp when thus temporarily deenergized for energizing said cooling means until normal operation is reestablished.

3. In combination with a high pressure vapor electrical discharge lamp and a source or power therefor, cooling means for said lamp, relay means electrically connected to the terminals of said lamp and'responsive to the approximate normal operating voltage thereof for energizing said cooling means, relay means in series with said lamp and responsive to current therethrough for deenergizing said first mentioned relay means when the voltage across the terminals of said' lamp becomes substantially higher than said normal operating voltage, and relay means electrically connected to the terminals or said lamp and responsive to voltages greater than said normal operating voltage but less than the voltage of said source for energizing said cooling means when the voltage across said lamp becomes substantially higher than normal operating voltage.

4. In combination with ,a high pressure vapor electrical discharge lamp and a source of power therefor, cooling means for said lamp, relay means electrically connected to the terminals of said lamp and responsive to the approximate relay of a voltage approximately equal to or less than the normal operating voltage of the discharge device.

6. In combination, a vapor electric discharge device of the type requiring artificial cooling for normal operation; cooling means for said device;

' a current relay comprising a coil and contacts actuated thereby, said coil being connected in.

series with the discharge device to close said contacts when current fiows through said discharge device; a voltage relay comprising a coil and a pair of contacts, said voltage relay contacts being normal operating voltage thereof for energizing said cooling means, relay means in series with said lamp and responsive to current therethrough for deenergizing said first mentioned relay means when said lamp becomes temporarily deenergized alter normal operation has once obtained, and.

relay means electrically connected -to the terminals of said lamp and responsive to voltages greater than said normal operating voltage for energizing said cooling means until normal operationisreestablished; I

5. In combination, a vapor electric discharge device of the type requiring artificial cooling for normal operation; cooling means for said device; a current relay comprising a coil and contacts actuated thereby. said coil being-connected in in an actuating circuit ior said cooling means, and said voltage relay coil being connected across the terminals or the discharge device through the current relay contacts, said voltage relay being operable to close the circuit to said cooling means 1 upon closure of said current relay contacts and application to said voltage relay of a voltage approximately equal to or less than the normal operating voltage of the discharge device; and a second voltage relay comprising a coil connected directly across the terminals or the discharge device. and a pair of contacts connected in an actuating circuit for said cooling means, said second voltage relay being operable to close the circuitto said cooling means only upon application thereto of a voltage greater than the normal operating voltage of the discharge device and less than the normal supply voltage.

CARLTON R. DUNHAM. VICTOR J. FRANCIS. 

